/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.iotdb.tsfile.read.common;

import org.apache.iotdb.tsfile.read.expression.IExpression;
import org.apache.iotdb.tsfile.read.expression.impl.BinaryExpression;
import org.apache.iotdb.tsfile.read.expression.impl.GlobalTimeExpression;
import org.apache.iotdb.tsfile.read.filter.TimeFilter;

import java.util.*;

/**
 * interval [min,max] of long data type
 *
 * <p>Reference: http://www.java2s.com/Code/Java/Collections-Data-Structure/Anumericalinterval.htm
 */
public class TimeRange implements Comparable<TimeRange> {

    /**
     * The lower value
     */
    private long min = 0;

    /**
     * The upper value
     */
    private long max = 0;

    /**
     * Initialize a closed interval [min,max].
     *
     * @param min the left endpoint of the closed interval
     * @param max the right endpoint of the closed interval
     */
    public TimeRange(long min, long max) {
        set(min, max);
    }

    @Override
    public int compareTo(TimeRange r) {
        if (r == null) {
            throw new NullPointerException("The input cannot be null!");
        }
        if (this.min > r.min) {
            return 1;
        } else if (this.min < r.min) {
            return -1;
        } else {
            if (this.max > r.max) {
                return 1;
            } else if (this.max < r.max) {
                return -1;
            } else {
                return 0;
            }
        }
    }

    public void setMin(long min) {
        if (min < 0 || min > this.max) {
            throw new IllegalArgumentException("Invalid input!");
        }
        this.min = min;
    }

    public void setMax(long max) {
        if (max < 0 || max < this.min) {
            throw new IllegalArgumentException("Invalid input!");
        }
        this.max = max;
    }

    /**
     * Check whether this TimeRange contains r.
     *
     * @return true if the given range lies in this range, inclusively
     */
    public boolean contains(TimeRange r) {
        return min <= r.min && max >= r.max;
    }

    public boolean contains(long min, long max) {
        if (leftClose && rightClose) {
            return this.min <= min && this.max >= max;
        } else if (leftClose) {
            return this.min <= min && this.max > max;
        } else if (rightClose) {
            return this.min < min && this.max >= max;
        } else {
            return this.min < min && this.max > max;
        }
    }

    public boolean contains(long time) {
        if (leftClose && rightClose) {
            return time >= this.min && time <= this.max;
        } else if (leftClose) {
            return time >= this.min && time < this.max;
        } else if (rightClose) {
            return time > this.min && time <= this.max;
        } else {
            return time > this.min && time < this.max;
        }
    }

    /**
     * Set a closed interval [min,max].
     *
     * @param min the left endpoint of the closed interval
     * @param max the right endpoint of the closed interval
     */
    public void set(long min, long max) {
        if (min > max) {
            throw new IllegalArgumentException("min:" + min + " should not be larger than max: " + max);
        }
        this.min = min;
        this.max = max;
    }

    /**
     * Get the lower range bundary.
     *
     * @return The lower range boundary.
     */
    public long getMin() {
        return min;
    }

    /**
     * Get the upper range boundary.
     *
     * @return The upper range boundary.
     */
    public long getMax() {
        return max;
    }

    /**
     * Here are some examples.
     *
     * <p>[1,3] does not intersect with (4,5].
     *
     * <p>[1,3) does not intersect with (3,5].
     *
     * <p>[1,3] does not intersect with [5,6].
     *
     * <p>[1,3] intersects with [2,5].
     *
     * <p>[1,3] intersects with (3,5].
     *
     * <p>[1,3) intersects with (2,5].
     *
     * <p>Note: this method treats [1,3] and [4,5] as two "intersected" interval even if they are not
     * truly intersected.
     *
     * @param r the given time range
     * @return true if the current time range "intersects" with the given time range r
     */
    public boolean intersects(TimeRange r) {
        if ((!leftClose || !r.rightClose) && (r.max < min)) {
            // e.g., [1,3] does not intersect with (4,5].
            return false;
        } else if (!leftClose && !r.rightClose && r.max <= min) {
            // e.g.,[1,3) does not intersect with (3,5]
            return false;
        } else if (leftClose && r.rightClose && r.max <= min - 2) {
            // e.g.,[1,3] does not intersect with [5,6].
            // take care of overflow. e.g., Long.MIN_VALUE
            return false;
        } else if ((!rightClose || !r.leftClose) && (r.min > max)) {
            return false;
        } else if (!rightClose && !r.leftClose && r.min >= max) {
            return false;
        } else if (rightClose && r.leftClose && r.min >= max + 2) {
            // take care of overflow. e.g., Long.MAX_VALUE
            return false;
        } else {
            return true;
        }
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        TimeRange that = (TimeRange) o;
        return (this.min == that.min && this.max == that.max);
    }

    @Override
    public int hashCode() {
        return Objects.hash(min, max);
    }

    /**
     * Check if two TimeRanges overlap
     *
     * @param rhs the given time range
     * @return true if the current time range overlaps with the given time range rhs
     */
    public boolean overlaps(TimeRange rhs) {
        if ((!this.leftClose || !rhs.rightClose) && (rhs.max <= this.min)) {
            // e.g., rhs:[1,3] does not overlap with this:(3,5].
            return false;
        } else if (!this.leftClose && !rhs.rightClose && rhs.max <= this.min + 1) {
            // e.g., rhs:[1,4) does not overlap with this:(3,5]
            return false;
        } else if (this.leftClose && rhs.rightClose && rhs.max < this.min) {
            // e.g., rhs:[1,4] does not overlap with this:[5,6]
            return false;
        } else if ((!this.rightClose || !rhs.leftClose) && (rhs.min >= this.max)) {
            // e.g., this:[1,5) does not overlap with rhs:[5,6]
            return false;
        } else if (!this.rightClose && !rhs.leftClose && rhs.min + 1 >= this.max) {
            // e.g., this:[1,5) does not overlap with rhs:(4,6]
            return false;
        } else if (this.rightClose && rhs.leftClose && rhs.min > this.max) {
            // e.g., this:[1,5] does not overlap with rhs:[6,8]
            return false;
        } else {
            return true;
        }
    }

    @Override
    public String toString() {
        StringBuilder res = new StringBuilder();
        if (leftClose) {
            res.append("[ ");
        } else {
            res.append("( ");
        }
        res.append(min).append(" : ").append(max);
        if (rightClose) {
            res.append(" ]");
        } else {
            res.append(" )");
        }
        return res.toString();
    }

    // NOTE the primitive timeRange is always a closed interval [min,max] and
    // only in getRemains functions are leftClose and rightClose considered.
    private boolean leftClose = true; // default true
    private boolean rightClose = true; // default true

    public void setLeftClose(boolean leftClose) {
        this.leftClose = leftClose;
    }

    public void setRightClose(boolean rightClose) {
        this.rightClose = rightClose;
    }

    public boolean getLeftClose() {
        return leftClose;
    }

    public boolean getRightClose() {
        return rightClose;
    }

    /**
     * Return the union of the given time ranges.
     *
     * @param unionCandidates time ranges to be merged
     * @return the union of time ranges
     */
    public static List<TimeRange> sortAndMerge(List<TimeRange> unionCandidates) {
        // sort the time ranges in ascending order of the start time
        Collections.sort(unionCandidates);

        ArrayList<TimeRange> unionResult = new ArrayList<>();
        Iterator<TimeRange> iterator = unionCandidates.iterator();
        TimeRange rangeCurr;

        if (!iterator.hasNext()) {
            return unionResult;
        } else {
            rangeCurr = iterator.next();
        }

        while (iterator.hasNext()) {
            TimeRange rangeNext = iterator.next();
            if (rangeCurr.intersects(rangeNext)) {
                rangeCurr.merge(rangeNext);
            } else {
                unionResult.add(rangeCurr);
                rangeCurr = rangeNext;
            }
        }
        unionResult.add(rangeCurr);
        return unionResult;
    }

    public void merge(TimeRange rhs) {
        set(Math.min(getMin(), rhs.getMin()), Math.max(getMax(), rhs.getMax()));
    }

    /**
     * Get the remaining time ranges in the current ranges but not in timeRangesPrev.
     *
     * <p>NOTE the primitive timeRange is always a closed interval [min,max] and only in this function
     * are leftClose and rightClose changed.
     *
     * @param timeRangesPrev time ranges union in ascending order of the start time
     * @return the remaining time ranges
     */
    @SuppressWarnings("squid:S3776") // Suppress high Cognitive Complexity warning
    public List<TimeRange> getRemains(List<TimeRange> timeRangesPrev) {
        List<TimeRange> remains = new ArrayList<>();

        for (TimeRange prev : timeRangesPrev) {
            // +2 is to keep consistent with the definition of `intersects` of two closed intervals
            if (prev.min >= max + 2) {
                // break early since timeRangesPrev is sorted
                break;
            }

            if (intersects(prev)) {
                if (prev.contains(this)) {
                    // e.g., this=[3,5], prev=[1,10]
                    // e.g., this=[3,5], prev=[3,5] Note that in this case, prev contains this and vice versa.
                    return remains;
                } else if (this.contains(prev)) {
                    if (prev.min > this.min && prev.max == this.max) {
                        // e.g., this=[1,6], prev=[3,6]
                        this.setMax(prev.min);
                        this.setRightClose(false);
                        remains.add(this);
                        // return the final result because timeRangesPrev is sorted
                        return remains;
                    } else if (prev.min == this.min) {
                        // Note prev.max < this.max e.g., this=[1,10], prev=[1,4]
                        min = prev.max;
                        leftClose = false;
                    } else {
                        // e.g., prev=[3,6], this=[1,10]
                        TimeRange r = new TimeRange(this.min, prev.min);
                        r.setLeftClose(this.leftClose);
                        r.setRightClose(false);
                        remains.add(r);
                        min = prev.max;
                        leftClose = false;
                    }
                } else {
                    // intersect without one containing the other
                    if (prev.min < this.min) {
                        // e.g., this=[3,10], prev=[1,6]
                        min = prev.max;
                        leftClose = false;
                    } else {
                        // e.g., this=[1,8], prev=[5,12]
                        this.setMax(prev.min);
                        this.setRightClose(false);
                        remains.add(this);
                        // return the final result because timeRangesPrev is sorted
                        return remains;
                    }
                }
            }
        }

        remains.add(this);
        return remains;
    }

    public IExpression getExpression() {
        IExpression left;
        IExpression right;
        if (leftClose) {
            left = new GlobalTimeExpression(TimeFilter.gtEq(min));
        } else {
            left = new GlobalTimeExpression(TimeFilter.gt(min));
        }

        if (rightClose) {
            right = new GlobalTimeExpression(TimeFilter.ltEq(max));
        } else {
            right = new GlobalTimeExpression(TimeFilter.lt(max));
        }

        return BinaryExpression.and(left, right);
    }
}
